Pin and sleeve combination to support dies in dentistry



July 7, 1970 H. SUSMAN EI'AL 3,518,761

PIN AND SLEEVE COMBINATION TO SUPPORT DIES IN DENTISTRY Filed Sept. 28,1967 INVENTORS HARRY SUSMAN JON E. SUSMAN ATTORNEY United States Patent3,518,761 PIN AND SLEEVE COMBINATION TO SUPPORT DIES IN DENTISTRY HarrySusman and Jon E. Susman, both of 6439 Prestonshire, Dallas, Tex. 75225Filed Sept. 28, 1967, Ser. No. 671,450 Int. Cl. A61c 13/00 US. CI. 32-1112 Claims ABSTRACT OF THE DISCLOSURE A pin and a sleeve that onlypartially surrounds it in supporting engagement are used in conjunctionwith a stone die and model. The pin has a rod portion which extends intothe die, with the pin base or shank extending outwardly from the die.The sleeve is set in the stone base of the model and is adapted toreceive the shank of the pin in order to support the removable die. Thesleeve is well supported in the stone since it has portions disposed toresist axial displacement with respect to the stone.

FIELD OF THE INVENTION This invention relates to dentistry, and, moreparticularly, to the fabrication of inlays and crown and bridgeprosthesis. The pin-sleeve combination of the present invention isutilized to support removable castings of the preparations, i.e., dies,on a stone model. The support so, provided is highly stable andmaintains the relative spatial relationships of the dies one to theother, and to the model, even though the dies be removed and reimplacednumerous times.

BACKGROUND OF THE INVENTION It is well known in the art to utilize animpression, followed by a casting in stone, to provide a model of apatients teeth and surrounding gum structure. As an example, if a singlemissing tooth is to be replaced by a prosthesis, typically a so-called3-unit bridge would be utilized. The immediately adjacent teeth oneither side of the missing one are prepared to receive and support theends of the bridge structure. At this point an impression is taken, asby hydrocoiloid, rubber base, silicones, etc., and from the impression,the shape of the teeth and the gum structure of the patient is cast indie stone. The integrity of the shape and the relative spatialrelationships of the castings of the preparations which support thebridge structure are most important if the prosthesis is to fitproperly. Moreover, it is necessary that the preparation castings beindividually removable or separable from the body of the stone castingin order to make the subsequent prosthesis possible. For this reason,the stone model ridge approximating the preparation casting is cut orsawed along an even line to provide for removing and replacing thepreparation castings as required. These resulting removable preparationcastings are known in the art as dies, and they will be hereinafter sodesignated.

The stone casting, including the dies, is mounted upon a stone base orsubstrate region of stone. This provides a working model of the preparedteeth and gum structure of the patient. Then this model is articulatedwith a stone casting of the opposing teeth. The bite of the patient isset up by this procedure. In such an articulated structure, the diesneed to be removable, and yet it is important that they be replaceablein precisely their original position. A popular prior art method ofproviding such removability is to insert a die pin member into thecentral base region of the preparation casting before the stone hashardened. The shank of the pin extends outward from the base of the die.Thereafter, a stone base is formed as a support for the die and theshank of the die pin extends into this base. The

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die may be removed by simply withdrawing the die pin from the matingrecess in the stone base. Replacement is accomplished by inserting thedie pin again into position in the stone base.

While the procedure described above has the advantage of simplicity, itpossesses a marked disadvantage. The removal and reinsertion of the diepin into the mating recess in the stone invariably wears the stonematerial that defines the recess. This occurs even when great caution isexercised. The results are most unfortunate. The die no longer issupportable in its precise original position, and as a result, thespatial relationship of the dies to each other, indeed to the balance ofthe model, is no longer accurate. This loss of accurate relative spatialpositioning results in inaccuracy in the prosthesis made from the model.

The present invention is directed to overcoming the problem justdescribed. It involves the provision of a sleeve member which onlypartially surrounds and encases the pin shank to provide support for it.The sleeve and pin as a unit are cast in the stone base, and the sleeveremains in the stone base as a stable support for the pin. When the pinis removed, or replaced, the rubbing or sliding contact is with therelatively tough sleeve, which remains in an integral relationship withthe stone.

It appears that a sleeve and pin combination has had limited use in thepast. In such combination, the sleeve served as a full scabbard for thepin and entirely surrounded it. The tolerance problems inherentlypresent in such an arrangement have caused the combination to beunsatisfactory since the pin, in most instances, moves laterally withrespect to the scabbard. Moreover, the full scabbard member of the priorart itself was susceptible to being axially unstable in the stone.Accordingly, the pin and full scabbard prior art combination was proneto cause both lateral and axial movement. The present inventionovercomes these problems with an inexpensive structure which is simpleto fabricate.

THE DRAWINGS FIG. 1 is a pictorial view of the pin-sleeve combination ofthe present invention, the pin and sleeve being shown in disengagedposition;

FIG. 1A is a section taken along the longitudinal axis of the pin-sleevecombination of FIG. 1, the pin and sleeve being in engagement in thisview;

FIG. 2 is a pictorial illustration of an impression tray carrying diestone in which two pin-sleeve members of the present invention aremounted;

FIG. 3 is a section taken along 33 of FIG. 2;

FIG. 4 is a pictorial view schematically illustrating a stone modelutilizing two of the die-pin members of the present invention;

FIG. 5 is a sectional view through a die and stone base and showingtheir engagement by means of the pin-sleeve combination of the presentinvention;

FIG. 6 shows the same subject matter as FIG. 5, except the stone baseand sleeve are shown alone, with the die pin and die removed; and

FIG. 7 is a pictorial illustration of a preferred embodiment of sleevewhich is adapted to be adjustable to eliminate tolerance problems.

DESCRIPTION OF A PREFERRED EMBODIMENT FIGS. 1 and 1A illustrate a diepin 11 and die sleeve 13. The pin comprises a pin shank 15 which isshaped generally as the frustrum of a four sided pyramid. Integrallyfrom the base of the shank concentrically extends a knurled support rod17 which is adapted to seat within a die, as subsequently will beexplained.

The sleeve 13 includes a pair of spaced apart generally rectangularframes 19 and 21. The frame 19 is larger than the frame 21, and both areconstructed so that the inner frame faces are at an angle correspondingto the angle of the faces of the pin shank 15. An integral strap 22connects and coaxially supports frames 19 and 21 in spaced relationship.Note that sleeve 13 is adapted to receive the pin 11, with frames 19 and21 in mating and supporting relationship with pin shank 15 (see FIG.1A).

It is preferred that outer frame 19 have a reverse taper, compared tothe sense of the taper of pin shank 15 (FIG. 1A). The importance of thisreverse taper will be explained at a later point herein.

The die pin 11 may be made of a variety of materials, since any materialmay be used that has good structural integrity and that is abrasionresistant, as contrasted to stone. The sleeve 13 is made of a materialwith similar properties. Exemplary of suitable construction materialsfor the pin and sleeve are stainless steel, aluminum, brass, copper andmetal alloys. In general, the material of construction will be a metal;however, other comparatively strong and abrasion resistant materials maybe utilized.

FIGS. 2 through 6 illustrate the utilization of the die pin and sleevecombination of the present invention. In FIG. 2, impression tray 30,carrying impression 31, is filled with stone 32. Note that impressiontray 30 is marked with indica 33 to provide a way to locate the castdies.

Die pins 11 extend upwardly from the central regions defining the baseof each die. The pins and mating sleeves 13 are placed in position as aunit after the stone is vibrated in the impression tray but before thestone hardens. Such emplacement is accomplished by inserting the knurledrod 17 of each pin and the upper portion of frame 19 into the die stone.Note that after insertion the frame 19 is partially embedded in thestone die, e.g. with about half the frame within the stone die and theother half extending above it.

The appearance of each die at the stage of FIG. 2 is schematicallyillustrated in FIG. 3, which is a schematic section applicable to eitherone of the dies being cast in FIG. 2. Note that knurled rod 17 and theupper portion of frame 19 extend into the central base portion of thestone die 35, which is surrounded by the impression 31, carried insupport tray 30.

After the step of FIGS. 2 and 3, the stone is permitted to harden. Aconventional release agent is applied over the die area and additionalstone is then poured over the casting carried by the impression tray 30.The wet stone is vibrated and then permitted to harden. This provides amodel stone base 39 (FIG. as is well known in the art. The sleeve 13,carrying the pin shank 15, of each die 35 is covered by the moist stonepreparation, and on setting, the sleeve 13 becomes embedded in thehardened stone base. Thereafter, the tray and rubber base impression areremoved and cuts, as by a saw, are made on either side of the dies inthe locations defined by indicia 33, and the dies are then separablefrom the model. The separation of the die from the model is facilitatedby the reverse taper of the frame 19, which permits the die to be easilyremoved from the frame.

The appearance of the resulting model is pictorially illustrated in FIG.4, wherein the removable dies 35 are carried by stone base 39 of themodel 41. The sleeves 13, with the exception of the end of frames 19,are embedded in and supported by the stone base 39. (FIGS. 4, 5 and 6).Each pin shank 15 is removable from its sleeve to define a mating cavityin the stone base (see FIG. 6). Moreover, since the sleeve onlypartially encases the pin, a large portion of the pins surface isencased with and supported directly by the stone base. Indeed, over halfthe supporting and encasing area for the pin is provided by directcontact with stone in the embodiment being described since the framesare spaced rather far apart, compared to their axial dimensions, andsince the planar interconnecting strap 22 for the frames lies along onlyone side of the pin.

Removal and replacement of the pin shank does not disturb the sleeve,which remains anchored in the stone base. The reverse taper of frame 19assists in assuring that the sleeve remains anchored, as do the embeddedend edges of frame 19 and frame 21.

It will then be apparent that the pin shank may be reinserted into thestone supported sleeve, and removed, as desired, without disturbing therelative positions of the dies to the model.

It should be noted that the reverse tapered frame 19 provides directsupport for the die since a part of the frame extends into the die whenthe die is emplaced on the model. This extension of the frame into thedie has another advantage. It makes it possible to vibrate the materialfrom which the stone base is being formed (before hardening of thismaterial) without dislocating the proper position of the sleeve 13.

It is preferred that the tip of pin shank 15 stick out of the bottom ofstone base 39 (FIG. 5). This is helpful in removing a die 35 since apush on the pin tip will loosen the die. This extension of the tip maybe obtained by removing stone from the bottom of the stone base after itis cast.

In some instances, despite reasonable care in manufacture, tolerances ofthe frames of the sleeve 13 and the pin v11 will not be compatible toprovide support against all lateral movement of the pin relative to thesleeve. The embodiment of sleeve member illustrated in FIG. 7 providesmeans to solve this problem. The frames 19a and 21a of sleeves 13a areseparated by slits at 109 and 111, respectively, in their sides oppositethe interconnecting strap 22a. Such slits make it possible to mash theframes together, as required, to closely engage and support a pinpositioned within the sleeve. By utilization of this embodiment,tolerance problems are eliminated.

In summary, the present invention overcomes numerous problems of theprior art. High quality crown and bridge prosthesis is an exactingscience demanding the absolute maintenance of spatial relationships. Thepresent invention meets this demand. The unique design of the pin andpartial sleeve firmly locks the sleeve in the stone base thus completelyeliminating any lateral or axial movement. Slits in the frames may beutilized to provide means to adjust for occasional manufacturingdeficiencies. The reverse taper of the larger sleeve frame has manyunique advantages. This frame not only helps lock the sleeve securely inthe stone base, but also facilitates the easy removal of the die pin. Inaddition, the upper edge of this frame is, in effect, a part of the baseof the die unit itself when the die is in position on the model. Thisfeature imparts great strength to the die (crown portion) makingbreakage of the die from its rod supports virtually impossible.

What is claimed is:

1. A dental pin-sleeve combination comprising:

(1) a pin having a tapered shank portion with anchor means extendingfrom one extremity thereof; and

(2) a partial sleeve adapted to receive said pin, comprising a pair ofspaced apart frames, interconnected by a strap portion, said frameshaving inner tapered surfaces generally parallel to the taper on saidpin to provide close engagement of the tapered surfaces of the pin andframes when said sleeve receives said pin, and at least one of saidframes having a reverse taper on its outer surfaces with reference tothe tapef of said shank. I"

2. The combination of claim 1 wherein one of said frames is larger thanthe other of said frames, and wherein the larger frame has a reversetaper on its outer surfaces.

3. The combination of claim 1 wherein said pin shank is generally shapedas the frustru-m of a four sided pyramid and said one frame having thereverse taper on its outer surface, and being adapted to receive andsupport the surface of said pin adjacent the base portion of saidfrustrum.

4. The combination of claim 3 wherein each of said frames is configuredto provide a generally axial slit therein.

5. The combination of claim 1 wherein each of said frames is configuredto provide a generally axail slit therein.

6. A dental pin-sleeve combination comprising:

(1) a pin having a shank portion with anchor means extending from oneextremity thereof; and

(2) a partial sleeve adapted to receive said pin comprising a pair ofspaced apart frames, interconnected by a strap portion, each said framecarrying surfaces that are adapted to mate with surfaces of the shankportion of said pin and provide lateral support thereof, and whereineach of said frames includes means to adjust its transverse dimensionsto permit tightening said frame to better laterally support said pin.

7. The combination of claim 6 wherein each of said frames is configuredto provide a generally axial slit therein.

8. A dental pin-sleeve combination comprising:

(1) a pin having an elongated tapered shank and anchor means extendingfrom an end of said shank; and

(2) a sleeve adapted to receive said pin, said sleeve including an innersurface portion adapted to mate with said pin adjacent the said end ofthe shank, said sleeve further including an outer surface portion havinga reverse taper with reference to the taper of said shank.

9. A dental pin-sleeve combination comprising:

(1) a pin having a tapered shank portion with anchor means forsupporting a die extending from one extremity thereof; and

(2) a partial sleeve adapted to receive said pin and only partiallyenclose the shank portion thereof comprising a pair of spaced apartframes interconnected by a strap portion, one of said frames beingadapted to extend partially within said die when receiving said pin.

10. The combination of claim 9 wherein one of said frames is larger thanthe other of said frames, and Wherein the larger frame has a reversetaper on its outer surfaces.

11. The combination of claim 10 wherein said pin shank is generallyshaped as the frustrum of a four-sided pyramid, and wherein said largerframe is adapted to receive and support the surface of said pin adjacentthe base portion of said frustrum.

12. The combination of claim 11 wherein each of said frames isconfigured to provide a generally axial slit therein.

References Cited UNITED STATES PATENTS 1,867,300 7/1932 Bailey 32403,286,350 11/1966 Cooper 324O ROBERT PESHOCK, Primary Examiner

